Every human culture has a wealth of symbols and symbol systems that support cognition and communication, and all children must master a set of culturally important symbols to participate fully in their society. They begin to do so very early, and the purpose of the research proposed in this application is to examine the advent and early course of this very important domain of development. The proposed studies focus on very young children's understanding and use of symbolic artifacts. The research falls into three general areas. (1) The majority of the studies concern 2- to 3.5-year-old children's use of various media (including scale models, pictures, and video) as a source of information about the location of a hidden toy. If they understand the symbol-reality relation, they can easily find the toy, but if not, they have no way of knowing where to search. Many of the proposed studies are designed to test or extend a conceptual model of young children's early symbolic functioning. (2) The investigators will also probe infants' very early steps in starting to acquire an understanding of pictures. (3) There is also a focus on the practical domain of young children's testimony; specifically, the use of self-symbols, such as dolls, for interviewing young children about suspected sexual abuse. The proposed research should expand our knowledge of the origins and early development of a vital aspect of cognition--symbolic functioning. Because symbols play a central role in so much of human thought and problem solving, a better understanding of the emergence of symbol use is of paramount importance. The research has important implications for educational practices using symbolic artifacts and for the improvement of young children's testimony.